FeetFinder is one of the largest feet-picture marketplaces in the world.
Alternatively, you can create your own group.
It was designed to create communities that share a love for similar things.
Protect yourself financially when selling feet pictures by using something like CashApp, or a platform like Patreon or OnlyFans.
There is even an entire website dedicated to feet pictures called WikiFeet.
You can sell to strangers, brands, media companies, or all of these entities.